232 results about "Logarithmic spiral" patented technology

A progressive gear assembly that is a vehicle steering gear, the assembly comprising at least one spur gear (1, 2) and a toothed structure (3, 4, 5, 7, 8) with which the spur gear (1, 2) meshes. The spur gear (1, 2) has teeth (11) arranged along a curve (10), the curve (10) comprising a radius of curvature (r) which monotonically rises over an angular range of more than 90° of the curve (10). Preferably the curve is a spiral, particularly a logarithmic spiral. This gear assembly is configured compact and simple, features smooth running and achieves a late end point.

A fitting (10), in particular for a motor vehicle seat, having a first fitting part (11), on which a gear rim (17) is formed and a second fitting part (12) on which a gearwheel (16) is formed. The gearwheel meshes with the gear rim (17), whereby the two fitting parts (11, 12) are in geared connection with each other. The fitting also has a rotatably mounted, revolving eccentric driven by a driving element for driving a relative rolling motion of gearwheel (16) and gear rim (17). During this rolling motion a tooth flank (16d) of a tooth (16a) of the gearwheel (16) rests against a tooth flank (17d) of a tooth (17a) of the gear rim (17) at a contact point (K). The tooth flanks (16d, 17d) of the teeth (16a, 17a) of the gearwheel (16) and gear rim (17) resting against each other at the contact point (K) each follow the course of a portion of a respective logarithmic spiral.

The invention relates to a centrifugal fan which comprises a fan frame and an impeller which is accommodated in the fan frame, wherein a channel is formed at the periphery of the impeller in the fan frame, one side of the fan frame is provided with an air outlet, the periphery of the fan frame is provided with an initial curve part and an expanded curve part connected with the initial curve part, the expanded curve part is placed at the rear side of the initial curve part along the direction of rotation of the impeller, the initial curve part extends along an Archimedean spiral or logarithmic spiral, the expanded curve part is placed on the outboard of the extended line obtained by extending the started curve part along the Archimedean spiral or logarithmic spiral, a guide plate is arranged in the fan frame, the guide plate extends from the air outlet to the channel, and the guide plate divides the channel into two airflow channels.

A vaso-occlusive device includes a microcoil formed into a minimum energy state secondary configuration comprising a plurality of curved segments, each defining a discrete axis, whereby the device, in its minimum energy state configuration, defines multiple axes. In a preferred embodiment, the secondary configuration comprises a plurality of interconnected closed loops defining a plurality of discrete axes. In a second embodiment, the secondary configuration defines a wave-form like structure comprising an array of laterally-alternating open loops defining a plurality of separate axes. In a third embodiment, the secondary configuration forms a series of tangential closed loops, wherein the entire structure subtends a first angle of arc, and wherein each adjacent pair of loops defines a second angle of arc. In a fourth embodiment, the secondary configuration forms a logarithmic spiral. In all embodiments, the device, in its secondary configuration, has a dimension that is substantially larger than the largest dimension of the vascular site (i.e., aneurysm) in which it is to be deployed. Thus, confinement of the device within an aneurysm causes it to assume a three-dimensional configuration with a higher energy state than the minimum energy state. Because the minimum energy state configuration of the device is larger (in at least one dimension) than the aneurysm, the deployed device is constrained by its contact with the walls of the aneurysm from returning to its minimum energy state configuration. The engagement of the device with the aneurysm wall minimizes shifting or tumbling due to blood flow. Furthermore, the secondary configuration is not conducive to “coin stacking,” thereby minimizing the compaction experienced.

A special shape of bars on refining discs or plate segments of a rotating disc refiner is disclosed including a plurality of bars generally extending outwards towards the outer end of the disk across its surface, arranged in a single, two or more radial zones, the plurality of the bars within a zone being curved with the shape of a logarithmic spiral. Disc refiners including such refining discs are also disclosed.

A special shape of bars on refining cones or plate segments of a rotating conical refiner is disclosed including a plurality of bars generally extending outwards towards the outer end of the cone across its working surface, arranged in a single, two or more radial zones, the plurality of the bars within a zone being curved with the shape of a logarithmic type spiral. Conical refiners including such refining cones are also disclosed.

A vaso-occlusive device includes a microcoil formed into a minimum energy state secondary configuration comprising a plurality of curved segments, each defining a discrete axis, whereby the device, in its minimum energy state configuration, defines multiple axes. In a preferred embodiment, the secondary configuration-comprises a plurality of interconnected closed loops defining a plurality of discrete axes. In a second embodiment, the secondary configuration defines a wave-form like structure comprising an array of laterally-alternating open loops defining a plurality of separate axes. In a third embodiment, the secondary configuration forms a series of tangential closed loops, wherein the entire structure subtends a first angle of arc, and wherein each adjacent pair of loops defines a second angle of arc. In a fourth embodiment, the secondary configuration forms a logarithmic spiral. In all embodiments, the device, in its secondary configuration, has a dimension that is substantially larger than the largest dimension of the vascular site (i.e., aneurysm) in which it is to be deployed. Thus, confinement of the device within an aneurysm causes it to assume a three-dimensional configuration with a higher energy state than the minimum energy state. Because the minimum energy state configuration of the device is larger (in at least one dimension) than the aneurysm, the deployed device is constrained by its contact with the walls of the aneurysm from returning to its minimum energy state configuration. The engagement of the device with the aneurysm wall minimizes shifting or tumbling due to blood flow. Furthermore, the secondary configuration is not conducive to “coin stacking,” thereby minimizing the compaction experienced.

An exemplary centrifugal fan includes a casing defining an air outlet, and an impeller in the casing. An air channel is defined in the casing between a sidewall of the casing and outermost free ends of the impeller. The sidewall includes a first curved section adjoining a second curved section. The first curved section is located at a more upstream portion of the sidewall than the second curved section along a rotation direction of the impeller. The first curved section extends along a part of an Archimedes spiral or a part of a logarithmic spiral. The second curved section is located farther away from the impeller than an imaginary extension line of the first curved section along the Archimedes spiral or the logarithmic spiral. An air guide plate is formed in the casing and extends from the air outlet to an inner region of the air channel.

A special shape of bars on refining cones or plate segments of a rotating conical refiner is disclosed including a plurality of bars generally extending outwards towards the outer end of the cone across its working surface, arranged in a single, two or more radial zones, the plurality of the bars within a zone being curved with the shape of a logarithmic type spiral. Conical refiners including such refining cones are also disclosed.